Troubleshooting And Maintenance - Singer 3337 Manual De Instrucciones

TROUBLESHOOTING AND MAINTENANCE

1. Thread Loops on Underside of Fabric
2. Bobbin Thread Showing on Top of Fabric
3. Upper Thread Breaking
4. Thread is Shredding
5. Thread Bunching at Beginning
6. Skipping Stitches
7. Bobbin Winding Difficulties
8. Bobbin Thread Breaking
9. Needles Breaking
10. Stitches Distorted
11. Fabric Puckers
12. Fabric Is "Tunneling" Under Stitches
13. Machine Not Feeding Fabric
14. Needle Threader Not Working
15. Loud Noise When Sewing
16. Machine Will Not Run
1. THREAD LOOPS ON UNDERSIDE OF FABRIC
Possible Cause: Thread looping on the underside of the fabric is always an indication that the
upper thread is not correctly threaded. This happens when the upper thread is not correctly
placed in the tension mechanism and has not been threaded through the take up lever.
Solution: Rethread machine, making sure to first raise the presser foot lifter
before starting to thread, so thread can be properly seated in the tension
mechanism and take up lever. (See Page 14)
To know if you have rethreaded the machine correctly, try this simple test:
• Raise the presser foot lifter and thread the top of the machine.
• Thread the needle, but don't put the thread under the presser foot yet. As
you pull the upper thread to the left, it should pull freely.
• Put the presser foot lifter down. As you pull the upper thread to the left, you should feel
resistance. This means you are threaded correctly.
• Put the thread under the presser foot, and then draw up the bobbin thread. Slip both thread
tails under the presser foot towards the back. Lower presser foot and begin sewing.
If you put the presser foot lifter down, but the thread still pulls freely (you feel no difference
whether the presser foot is up or down), this means you have threaded incorrectly. Remove the
upper thread and rethread the machine.
2. BOBBIN THREAD SHOWING ON TOP OF FABRIC
Possible Cause: Top thread tension too tight.
Solution: Reduce upper thread tension. (See Page 18)
Possible Cause: Thread path is obstructed, putting extra tension on top thread.
Solution: Check that the top thread path is not obstructed and thread is moving freely through
the thread path. (See Page 14)
Possible Cause: Bobbin thread not in bobbin case tension.
Solution: Rethread bobbin. (See Page 13)
Troubleshooting
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